Agape is the love of humanity. It is the kind of love which makes us sorrowful when we hear of a crisis in another nation (or our own); that makes us give our time or money to charity; and makes us feel connected to people we don’t know simply on the basis of our shared experience as human beings.
Perhaps the most radical of all, was agape or selfless love. This was a love that you extended to all people, whether family members or distant strangers. Agape was later translated into Latin as caritas, which is the origin of our word “charity.”
“Compassion is the basis of morality.” – Arthur Schopenhauer
C.S. Lewis referred to it as “gift love,” the highest form of love. But it also appears in religious traditions, such as the idea of mettā or “universal loving kindness” in Theravāda Buddhism. Currently, there is growing evidence that agape is in a dangerous decline in many countries.
See other: Kinds of Greek Love
Knowledge Guild 
I like your Schopenhauer quotation, to a degree, it echoes de Waal: